1. Field of the Invention
The present invention relates to a multiple material golf club head. More specifically, the present invention relates to a multiple material golf club head with a compression-molded, thin-walled aft body.
2. Description of the Related Art
The prior art discloses multiple material golf club heads.
There are various problems with the current process for manufacturing multiple material golf club heads.
One problem is with the standard compression molding process, the hard metal tooling on both sides of the part makes undercuts impossible without significant increases in tool complexity.
Another problem is the molding compounds are not designed to be used in parts with very thin walls. When wall thicknesses are below approximately 0.080 inches, most standard molding compounds are difficult to compression mold.
Another problem is that standard molding compounds are not as strong, stiff, or tough as laminated composites made with similar matrix and fiber types.
Another problem is the raw materials for the current laminates are quite expensive. The cost is compounded by the very high scrap rate.
Another problem is that using prepreg requires hand placement of each layer of material into a mold which is a time-consuming and labor-intensive process.
Another problem is that with current latex bladders we are able to avoid undercut constraints, but we lose definition on the inside of our parts. The metal tooling dictates OML of the parts quite well, but the part thickness and IML are determined by the number of plies placed in each area and the amount of pressure exerted on the area by the bladder during the cure. As a result, it is difficult to predict the mass properties of the Fusion body before a part is made. One-piece bladder molded driver bodies do not work well with a body-over-face joint. The lack of precision on the inside of the head makes it difficult to control the geometry of the body where it would meet up with the face. Bladder molded multiple material driver design had been restricted to body-under-face joints so that the body bond surface is a well controlled OML surface. Typical epoxy-based prepregs are designed to cure in 20-30 minutes. In the current multiple material golf club head fabrication process, the latex bladders used to apply pressure during the cure cycle can only be used 2 or 3 times before they need to be discarded. Bladders are a significant cost in the current multiple material driver manufacturing process.